This invention relates to a boat trailer for transportation of boats.
Many boat trailers have been proposed and manufactured previously. Examples are shown in U.S. Pat. Nos. 4,529,217 (Wood); 4,895,387 (Hawkins); 4,858,943 (Cote); 4,781,392 (Cooper); 4,754,988 (Hofgren) and 4,623,161 (Sprague). Many of the above patents show an arrangement of trailer which supports the boat on the trailer frame by bunks which comprise elongate beams extending longitudinally of the boat with a relatively large upper surface which is often covered with a resilient material to provide support for the boat during transportation while avoiding high stress points which can damage the surface of the boat.
Many boat owners prefer to transport their boat on a trailer of this type including bunks in order to avoid damage to the boat surface. There is however a significant problem in unloading the boat from a trailer of this type in that the boat is relatively heavy and does not slide effectively on the bunks.
Some of the above patents show rollers on which the boat can roll. Other trailer types comprise simply rollers for supporting the boat which of course enables simple rolling of the boat across the rollers into the loaded position. However the rollers tend to damage the surface of the boat during transportation in that they provide relatively high stress points in view of the very small area of contact.
A further problem which arises in relation to boat trailers is that of theft since the unit is usually parked unattended in a yard or driveway when not being used. In addition the boat trailer generally does not include any support structure at the forward end so that when left by the vehicle it is simply inclined forwardly and downwardly toward the ground. This can cause water to collect in the boat at the forward end which makes it very difficult to lift the trailer when it is required to be connected to the hitch.
Various forms of jack arrangement are provided in the prior art and examples are shown in the U.S. Pat. Nos. 2,865,658 (Dubuque); 3,841,663 (Proffit); 3,989,276 (Hamerl); 4,619,463 (Weaver); 3,791,676 (Spratlen) and 4,469,348 (Crook). The last of these patents discloses a device which comprises a spare wheel support on which is attached a loop type structure pivotal from a rearward retracted position lying along the underside of the hitch to a forward deployed position in which it extends downwardly into contact with the ground. The loop type support can be locked in the forward position. This device is however relatively complicated and has a number of disadvantages.